Wooden pallets have long been the bane of any industry in which goods are shipped in packaged quantities, particularly in the packaging and transport industries. The typical wooden pallet comprises two decks arranged in a parallel planar relationship separated by two stringers and a center support member. The decks are spaced apart a sufficient distance so as to allow the prongs of a pallet jack, forklift, or similar lifting device to be positioned therebetween. The top deck can be a solid sheet of plywood or similar material. More often than not, the top deck is a series of slats spaced a distance of usually one half to one inch from each other. The bottom deck is usually a series of slats similar to those of the top deck but spaced greater distances apart from each other to allow the wheels on the prongs of a pallet jack to be accommodated therebetween, thus allowing the pallet to be lifted with the lifting device.
In most of the wooden pallet designs, the stringers are positioned on opposing edges of the spaced-apart decks, thereby limiting lifting device access. The center support member is usually positioned parallel to and halfway between the stringers to provide support at the center of the top deck. The stringers typically contain cut outs or recessed areas on the lower edges that are positioned adjacent the bottom deck to limit the amount of wood needed to construct the pallet, thereby conserving weight. These cut outs or recessed areas are weak points at which the stringers may stress and crack or bend under the weight of a load positioned on the top deck. Cracking or bending of any of the various parts of the pallet puts the goods stacked on the pallet at risk for being spilled or damaged.
Pallets incorporating such a design are limited to being arranged on vertical racks or on a flooring surface in a single orientation that allows the lifting device to have access to a single pallet while having to manipulate the least number of pallets. In other words, because the pallet allows a lifting device access from only two sides, the arrangements of loaded pallets should be such that those two sides all face the same directions. To arrange loaded pallets in any other configuration would cause an unnecessary amount of pallets to have to be moved to gain access to one pallet surrounded by others.
Other wooden pallet designs comprise two decks configured as above but being separated by about nine blocks positioned therebetween as spacers. This design allows a lifting device to gain access from all four sides of the pallet. However, problems of stresses associated with the above-mentioned pallet design still exist and continue to present obstacles to the efficient use of this type of pallet in the packaging and transport industries.
In addition to the overall designs of wooden pallets, the material of fabrication itself poses problems for the industries that utilize the pallets. The useful lifetime of the typical wooden pallet is only about one year. In an era when “green is clean”, the destruction of a natural resource, viz., trees, to fabricate pallets having a relatively short lifetime becomes an unpopular event that has come under fire from legislative bodies as a result of pressure exerted on politicians from environmental groups. After a certain amount of use, repair of a wooden pallet is futile and continued reparation becomes a cost-prohibitive factor in the pallet's maintenance. Millions of broken pallets are committed to waste every year, and, because many pallets have been contaminated with product that is not environmentally friendly, a large percentage of pallets must be destroyed as chemical waste.
Other problems associated with wooden pallets include handling difficulty due to their excessive weight and dimensional instability due to the ability of the wood to dry, crack, warp, swell, or rot. Furthermore, because the wood tends to absorb water, wooden pallets kept outside often become breeding grounds for undesirable fauna. Additionally, the various components of the wooden pallet are typically nailed or fastened together with similar implements, and pallet damage often results in the nails or fasteners being partially removed from the wood where they pose a potential hazard. In other instances, the nails or fasteners are completely removed from the wood only to be subsequently found in the tires of the lifting devices.
Plastic pallets provide an alternative to wooden pallets and are superior to the wooden pallets in many respects. The weight of the plastic pallet, however, remains a problem because of the need for significant amounts of reinforcement materials in the decks of the pallet to enable it to meet the load bearing capability of the wooden pallet, particularly when the loaded pallets are stored in racks where the pallet is supported only by rails at two edges and suspended therebetween. If both decks are reinforced, the weight requirement of the pallet is exceeded. Therefore, manufacturers of rackable plastic pallets currently limit the use of reinforcements to either the upper or lower deck. If the support is in the lower deck, the pallet often has difficulty passing the deflection limit specification while being lifted from the underside of the upper deck. It may also fail the deflection limit specification due to upper deck sag under static load, which can reduce fork lift gap size. If the support is placed only in the upper deck, the pallet will fail when lifted from below the lower deck or when riding on a chain conveyer system, which requires the lower deck to be rigid.
A new type of pallet is needed that overcomes the drawbacks of wooden pallets, yet meets the weight requirements as outlined by the GMA.